The present invention relates to a fuel tank for an engine, and it particularly relates to a fuel tank for a small-sized portable engine of a mowing machine or the like.
In a small-sized portable engine used for a mowing machine or the like, a fuel tank is generally installed on a lower part of the engine, and is made of resin for reduction in weight. The fuel tank is located near a muffler for reduction in size of the entire body of the engine, whereby it is also located in the place that is easily influenced by heat.
Fuel tanks are conventionally made of, for example, polyethylene, and in many cases, made by blow molding. However, since blow-molded polyethylene has low heat resistance, it is necessary to prevent an increase in temperature caused by the heat of the muffler, and therefore, a heat insulating plate being a separate component is provided between the muffler and the fuel tank. Japanese Utility Model Application Publication No. 56-53051 discloses one of the examples. According to Japanese Utility Model Application Publication No. 56-53051, an insulating body projected to a side portion of a crankcase is provided between a muffler and a fuel tank, and a lower portion of a muffler cover is connected to the insulating body to eliminate a space between the crankcase and the muffler to insulate the muffler from heat and prevent the temperature of the fuel tank from rising.
Further, since polyethylene has low abrasion resistance, the stands for placing the engine on the ground and the like are attached as separate components. Japanese Utility Model Application Publication No. 54-36166 discloses an example of this. According to Japanese Utility Model Application Publication No. 54-36166, it has the structure in which the fuel tank is installed on the engine body with use of a band and the band is provided with stand parts.
Further, in mowing machines, the cooling fan takes in scattering grass, which attaches to the cooling fan and the cooling fins of the cylinder, whereby cooling performance is reduced. As a countermeasure against this, in some mowing machines, a grass entry preventing guard is attached near the air inlet port of the cooling fan as a separate component.
However, in the structures of the conventional engines as described above, the insulating plates, the stands, and possibly the grass entry preventing guard are attached as separate components. This results in complicated structures, a large number of components, and many man-hours needed for assembly. This causes the disadvantage of increasing the cost of the engine.
The present invention is made in view of the aforementioned disadvantages, and its object is to provide a fuel tank for an engine in which the production cost can be reduced, due to a simple structure and less components.
In order to attain the aforementioned objects, a first aspect of a fuel tank for an engine according to the present invention is a fuel tank installed on a crankcase of an engine, having a face opposing a muffler, and a heat insulating part integrally formed on the face of the fuel tank opposing the muffler.
According to the above configuration, to prevent the temperature of the fuel tank from rising due to the heat of the muffler, a heat insulating part is integrally formed, thus causing the number of the components to be reduced, and a reduction in the number of man-hours for assembly. Accordingly, the engine can be produced at low cost.
A second aspect of the fuel tank for the engine according to the present invention is a fuel tank installed on an engine, with a stand part integrally formed.
According to the above configuration, since the fuel tank is provided with the stand part, the engine and the fuel tank can be placed with stability by means of the stand part. Further, since the stand part is integrally formed, the number of components and the number of man-hours for assembly are reduced, thus making it possible to produce the engine at low cost.
A third aspect of the fuel tank for the engine according to the present invention is a fuel tank installed on the engine via a space communicating with a cooling air inlet port through which cooling air for the engine is taken in by means of a cooling fan.
Grass entry preventing plates for preventing grass from entering the cooling air inlet port are integrally formed on an outer face facing the space communicating with the cooling air inlet port.
According to the above configuration, since the grass entry preventing plates are provided, grass collides against the grass entry preventing plates and falls, thus making it possible to prevent grass from being caught in the cooling fan and the cooling fins of the cylinder and reducing cooling performance. Further, since the grass entry preventing plates are integrally formed, the number of components and the man-hours needed for assembly are reduced, thus making it possible to produce the engine at low cost.